In July 2022, regions with elevations exceeding 5 000 m on the inner Tibetan Plateau (TP) witnessed a record-breaking heatwave. But how the atmospheric circulation and soil moisture play roles in the occurrence and maintenance of the heatwave in such high elevation climate sensitive region remains unknown. Here, by using the flow analogue method, we find that negative soil moisture anomalies explain more than half of the extreme high temperature during the heatwave, while atmospheric circulation explains less than half. The high soil moisture-temperature coupling metric and the increased correlation between latent heat flux and soil moisture during heatwave revealed strong land-atmosphere feedback in the Qiangtang Plateau which has amplified the heatwave. Analyses of numerical experiments confirm that the presence of interaction between soil moisture and the atmosphere has increased the intensity of hot extreme event under the same atmospheric circulation conditions. Under the warming background, land-atmosphere coupling leads to a faster increase in extreme high temperatures compared to the global mean warming rate, and it is twice as fast as the increase in extreme high temperatures without coupling. We highlight the increased probability of extreme high temperature over the TP in the future due to soil moisture feedback and the results are hoped to inform policymakers in making decisions for climate adaptation activities.

中文翻译：

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地气耦合放大了2022年7月青藏高原海拔5000米以上创纪录的热浪


2022年7月，青藏高原内陆海拔超过5000米的地区遭遇了创纪录的热浪。但在如此高海拔气候敏感区，大气环流和土壤湿度如何在热浪的发生和维持中发挥作用仍不清楚。在这里，通过使用流动模拟方法，我们发现土壤湿度负异常解释了热浪期间一半以上的极端高温，而大气环流解释了不到一半。热浪期间土壤水温耦合度高以及潜热通量与土壤湿度之间相关性增强，揭示了羌塘高原强烈的陆地-大气反馈，从而放大了热浪。数值实验分析证实，在相同大气环流条件下，土壤水分与大气相互作用的存在增加了极端高温事件的强度。在变暖背景下，陆地-大气耦合导致极端高温上升速度较全球平均变暖速度更快，是无耦合情况下极端高温上升速度的两倍。我们强调由于土壤湿度反馈，未来青藏高原出现极端高温的可能性增加，希望结果能够为政策制定者做出气候适应活动决策提供信息。